不同人工湿地系统中植物的生长特征及净化能力差异

以美人蕉、芦苇、香蒲、黄色鸢尾、水菖蒲、茭白为供试植物,以河沙和青砂为供试基质,通过模拟不同的人工湿地系统研究了植物生长特征及其人工湿地净化能力的变化.结果表明:与河沙处理相比,河沙+蚯蚓处理和河沙+青砂+蚯蚓处理中美人蕉的株高分别增加了42%和47%,叶长分别增加了36%和49%,株径分别增加了28%和20%;同样地,黄花鸢尾的株高分别增加了33%和23%,叶长分别增加了39%和29%,且水菖蒲的株高分别增加了53%和32%.与河沙处理相比,河沙+蚯蚓处理,河沙+青砂+蚯蚓处理中水菖蒲的SPAD值分别增加了20%和30%,黄花鸢尾的SPAD值分别增加了59%和65%,美人蕉的SPAD值分别增加了18%和11%.与对照人工湿地(CK)相比,人工湿地Ⅰ(河沙+植物)、人工湿地Ⅱ(河沙+植物+蚯蚓)和人工湿地Ⅲ(河沙+青砂+植物+蚯蚓)对COD的去除率分别增加了20%,24%和26%,对TP的去除率分别增加了14%,15%和19%,对NH₄-N的去除率分别增加了17%,23%和21%,对TN的去除率分别增加了5%,15%和12%.人工湿地Ⅱ中茭白、芦苇、水菖蒲和黄花鸢尾的密度高于人工湿地Ⅲ.粒径较小的河沙有利于植物的生长和氮的去除,而粒径较大的青砂对磷有较高的去除率.

Plant growth characteristics and purification capacity in different constructed wetland system

The growth characteristics and purification capacity of wetland plants in different constructed wetlands was studied by simulating different wetland system with six tested wetland plants (Canna indica,Phragmites Australis,Typha angustifolia,Iris pseudacorus L.,Acorus calamus L.and Zizania caduciflora) and two substrates (sand and green sand).Results show that earthworms in the constructed wetland can promote the growth of plants.Compared with plants in sand substrate,plants in treatment of sand plus earthworm or sand plus green sand and earthworms grow better in terms of plant height,leaf length,and plant diameter,especially for plant Canna indica,Iris pseudacorus L.,and Acorus calamus L..The chlorophyll content,measured by term SPAD(Soil and Plant Analyzer Development) is also improved by earthworm.The adding of substrate(sand or green sand) combined with plant and earthworm increases the purification capacity of the simulated wetland,in terms of removal efficiency of COD,TP,NH₄-N,and TN.Sand of mall particle size is beneficial to plant growth as well as nitrogen removal,while green sand with relatively large particle size has higher capacity to remove phosphorus.